Method and means for sustaining musical tones



July 30,. 1929. J. H. HAMMoND, JR

M ETHQD AND MEANS FOR SUSTAINING MUSICAL TONES Original Filed Aug. l2, 1925 5 Sheets-Sheet July 30, 1929. J. H. HAMMOND, JR

METHOD AND MEANS FOR SUSTAINING MUSICAL TONES Original Filed Aug.12. 1925 5 Sheets-Sheet 2 July 30,1929. 1, H. HAMMOND. JR 1,722,980

METHD AND MEANS FOR SUSTAINING MUSICAL TUNES Original Filed Aug. l2. 1925 5 Sheets-Sheet 5 July 30, 1929. J. H. HAMMOND, JR I 1,722,980

METHOD AND MEANS FOR SUSTAINING MUSICAL TONES Original Filed Aug. l2, 1925 5 Sheets-Sheet 4* ab... l s

July 30, 1929. J, H, HAMMOND, JR 1,722,980

METHOD AND MEANS FOR SUSTAINING MUSICAL TONES Original Filed Aug. l2. 1925 5 Sheets-Sheet 5 F/WVLZ@ 0 v Mo D Egt 60 1 W l i i .f/ Zl/'KZZ/a 0 75 Jzmayfnmfn Patented July 30, 1929.

UNITED STATES JOI-IN HAYS HAMMOND, JR., OF GLOUCESTER, MASSACHUSETTS.

METHOD AND MEANS FOR SUSTAINING MUSICAL TONES.

Application led August 12, 1925, Serial No. 49,824. Renewed May 16, 1929.

This invention relates to musical instruments of t-he percussive type and especially to pianofortes and to means for improving the operation of such instruments.

The invention has reference to the improved control of the decrement of damped musical tones, and to imparting to the music, new and agreeable effects, and to improving the quality of tone produced by al particular instrument.

As an aid to the understanding of the present invention, the following characteristics of percussive musical instruments are cited. ln any instrument of the percussive type for producing highly damped compressional waves having frequencies corresponding to the notes of the musical scale, the normal decrement of the waves of' a given frequency are thought to depend at leastin part upon such factors as the amount of energy imparted to the sound source, the characteristics of the sounding board or other resonant element, and of the Kcasing forming the resonant chamber' of the instrument. It is thought that these factors also aid in determining t-he timbre or musical quality yof the tones produced. By varying the decrement of the damped waves the notes can be sustained for varying lengths of time in accordance with the effect it is desired to produce, and an important feature of the present invention is to control the decrement or damping of the notes to produce a desired effect.

Another object of the invention is to reduce the decrement and thus to sustain the notes for an increased period of time by what may be called for convenience of expression, regeneration. According to this feature a reficx action is employed for causing the energy of the sound waves to be again imparted to the sound source to reenergize it. l'Vhen the source comprises tuned strings, as in a. piano, the wave trains may be reflected in varying degrees, back to the source, and the strings and sounding board kept in vibration for considerable periods. The energy of the waves may thus be utilized efficiently, and many new and novel effects may be imparted to the music by varying the amount of energy reflected back relative to the amount emitted.

I have discovered that by sustaining the tones for a considerable period, and by confinin g the compressional waves within a resonant chamber, the intensity of sound increases and decreases periodically. This produces a beat effect which is a particularly novel and attractive effect with percussive instruments. It is thought that this beat effect is probably explained by a production of reflected waves which are alternately in phase and out of phase with the Waves originally produced, thus alternately increasing and decreasing the intensity of sound.

I have also discovered that by providing centrally pivoted sound reflecting devices, improved control of sound refiection and regeneration is obtained, and thus there is effected a greatly increaseddelicacy of volume control and improved tone quality.

Another important feature of the present invention is to direct the sound waves produced by strings tuned to a particular note towards the strings tuned to the next higher harmonic of that note. Thus the energy of the waves is utilized to cause sympathetic vibration of the strings tuned to the upper harmonic and these strings in turn are caused to produce sound1 the effect of which is to increase the brilliance of the instrument.

Other objects will appear from the follow- L ing description taken in connection with the accompanying drawings, in which Figure l is a plan view of a grand piano embodying one form of the invention;

vFigure 2 is a front elevation with parts broken away of the piano shown in Figure l;

Figure 3 is a bottom plan view on the line 3-3 of Figure 2;

Figure 4 is an. enlarged view of a. portion of Figure 2;

Figures 5, 6 and 7 are detailed sections of the reflectors shown in Figure 2, positioned in fully closed, partly opened and fully Aopened positions respectively;

Figure 8 shows diagrammatically a group of centrally pivoted reflectors in closed position;

Figure 9 shows a group of edgewise pivoted reflectors in fully closed position; and

Figures 10, 11 and l2 show graphically variations in area of reflecting surface with the different strings of Figures 8 and 9, respectively.

Like reference characters refer to like parts in the several figures of the drawings.

In the following description and claims, parts will be identified by specific names for convenience of expression, but they are intended to be generic in their application to similar parts or equivalen-'t construction as the art will permit.

lleferrine` to the drawings there is shown so much ol' a grand piano 10 as is -i to understandinp` of the present invention, and having' applied 'thereto the features of the present invention. The embodiment illustrated comprises a grand piano 10 having for the purpose of producing sound a plurality of tuned strings such as l1 .tuned to the notes of the musical scale. lt will be understood that lthere maybe provided for each note of the musical sca-le one or more of such strings as may be desired. For eX-' sion there provided a suitable hammer AVaction such as 13 operatively connected Vto one of .the keys 14 of the manual of the piano. The strings are 4positioned Within a casing .Y Whicl is mounted upon .a plurality of feet -so that the manual comprising the keys l is positioned at `convenient height above `floor. Belote7 the manual and secured :he louer Wall of the casi-ngl 15., there is vided a pedal block l? upon which there positioned a lplurality of pedals, shown Yhree-i; number, as at 1S, 19, 20. The tivo rightdiand pedals seen in Figure 2, desigi respectively 19 and 20 are connect-ed to the sostenuto and loud pedal actions of the piano in a. conventional manner, and having no bearingv on the present invention, need not be further 'ribed The left-han d pedal 18 is pivotally mounted in the block 1'? and is operatively connected to a *'.fertically reciprocating red 21 the upper ene. of which enga-ges one arm of e ed bell crank lever 26. rlhe arrange- "te d such that when the pedal 18 is dcssed by the inusi n the rod 21 is raised the bell `cruilr. lever 26 is rotated in a and eounterscloclrwise direction vas lseen in Figure 2. l springl such as a leaf spring 2S is mounted en the casing of the piano and is arranged to .va-ct upon the bell crank lever 2G so as to maintain the bell crank lever and associated parts in the norm-al position illustrated in Fi ure. The opposite arm zofthe ybell crank lever 26 is pivotally .connected vby means of a connecting rod 30 to a rotatable arm -31 affixed zto the lower `end :of a rotatable shaft 82. The shaft 32 is ournalled in spaced beari 33, Slmounted upon thecasing 15 of the .p.ano Aand extends through fthe casing` to the upper portion of the piano. The shaft 32 is provided with a lined 'collar for main- .taining` the shaft in fixed longitudinal position with respect to its bearings. An arm 36 is a'llied to the shaft below the lower Wall of the casing' 15 and is pivotally connected at its outer end to a link 37 extending` to one end of a reciprocating connecting,l rod 38. Similarly there is secured to the shalt 32 near the upper Wall of the casing 15 an arm 39, the outer end of which is pivotally conneet-ed ,by means of a connecting link 40 to a reciprocating connecting rod 41. Y

The ceasing` 15 of the pian-o is provided with oppositeljvv disposed controllable apertures as at 50, 5l (see Figure 2) .and the boundary Walls interniediate these apertures may be constructed to include a layer 52 of substantiallg7 sound insulating material. Mounted in the upper aperture is a series of reflectors as at 53,' therefor, serving` to control the Y emission of sound. Each reliector 53 is preferably in the form of kan elongated, yflat member hai/'ing beveled lateral edges and pivotally mounted to rotate about its longitudinal axis (see Figure 4). Each reflector lis provided aon its inner surface with a layer 54 of sound reflecting' material which may be of sheet metal having a smooth surface such as sheet aluminum, and on its kouter face with an arm upper series of reflectors are pivotally connected to the upper connecting rod el.

ln the lower aperture 51 of the casing` there is mounted a second series of reflectors to con trol the emission .of sound.. The construction'of the lower group of reflectors corresponds Vto that of the upper group and includeo for each reflector a soundrciecting laye-r on the inner face which in this .case is .the upper face. VThe outer ends .of vthe arms 55 of the reflectors of the lower group are pivotally connected to the lower connecting rod Surrounding` each of the apertures the `casing` includes upper Wall 56, and a lower Wall 5? s-lzirting .the respective apertures, and havingl the edge beveled to conform .the edge of the contiguous reflector 53 and harircj on the inner face alayer of sound relecti T5 inatrial 58.

Y rlhe interior fa ce the intermediate boundary walls of the casing is `use provided with a layerof similar sound reflecting' naterial 59. Y Y

There are thus formed tivo rosen-ating ohanrl ers, one designated -by the reference character -GO Ventend g vbetween the upper series -of reflectors and the sounding board, and a second reso-natinfg' cham-ber designated 161 /see 2) Yeaten,ding` between the soundboard and the leave-r Aseries .of reflectors.

In operating, the manual the piano is employed .by .the musician inthe usual Way to The outer ends of the arms 55 of the that it is desired to sustain some of the notes of the music. Accordingly the pedal 1S is held down and thus the rod 21 is moved upwardly so as to rotate the bell crank lever 2G iu a counter-clockwise direction as seen in Figure 2. The connecting link 3l) and the connecting rods 41 and 38 are moved to the right and thus the reflectors 53 of the upper group of reflectors are rotated in a clockwise direction and the reflectors of the lower group are rotated in a counter-clockwise direction. Assuming that the pedal 1S has been fully depressed the reflectors are thus adjusted into the fully closed position with the respective apertures closed. The reflecting surfaces 511 of the reflectors, in combination with the reflecting surface 59 of the intermediate boundary walls of the casing 15 serve to reflect the energy of the compressional waves produced by thestrings back to the strings and sounding board thus serving to impart the energy of the waves, by reflex or regenerating action again to the strings and sounding board. The vibration of the strings and sounding board is thus sustained for a considerable period. The eiect of this is to produce a great improvement in the sonority of any pianoforte, sustaining chords and single notes in all registers of the scale to a remarkable degr Y e. The sounding board in the usual type of pianoforte is but weakly affected, moreover, by the overtones, but I h ave found that where the impulses are successively repeated by reflection, the sounding board is more strongly vibrated and the pianoforte gains an unusual brilliancy `with all the refiectors closed and in thc horizontal position. It is understood that the usual piano action 13 includes damping action operable in a well known manner for preventing vibration of the strings, but that this damping action may be rendered ineffective automatically by depression of the respective key or by means of the so-called loud pedal 9.0 of the piano. IVith the shutters fully closed, the waves are emitted for example, from a string 80 (see Figure 5) and one series of waves emitted therefrom take the path indicated by the arrow 81 towards the sounding board 62 and are reflected therefrom in a path indicated by the arrow 63 into contact with the reflecting surface 54 of one of the reflectors 53, again being` reflected into a path indicated by the arrow 611. This action may be sustained for a considerable time and it is clear that as the waves are reflected back and forth they will strike the strings and will tend to continue the vibration of the strings.

When it is desired to emit at least a portion of the sound produced within the casing 15 the pedal 18 is raised somewhat and this motion is communicated to the reflectors 53 causing them to be partially opened and to assume for example, a position such as indicated in Fig. 6. In this instance the compressional waves produced by the string SO and taking for example a path shown by the arrow G5, will be reflected from the surface 54; of the closures 53 into a path represented by the arrow GG. By suitable adjustment of the controlling pedal 18 the waves can be caused to impinge upon the strings tuned to the first upper harmonic of the note to which the string 8O is tuned and represented as at 67 and thus the strings 67 will be vibrated in sympathy with the waves differing by one octave from its own period of vibration. This produces a marked increase in brilliance of the piano and improves the quality of tone.

lVhen it is desired to emit a still greater proportion of the sound, the pedal 1S is moved upwardly to a greater degree and thc reflectors 53 take the position indicated diagrammatically in Fig. 7 where the waves from the string 80 may take the path indicated by the arrows 68, 69, and also the path indicated for example by the arrows 71, 72, thus causing a marked increase in amplitude of tone, but increasing the decrement of vibration of the resonating elements within the case.

Referring to Figs. 8 and 9 there are shown two contrasting forms of reflecting' devices, that shown in Fig. S being of the centrally pivoted type hereinbefore disclosed, and that shown in Fig. 9 being of the type hinged at the edge such as shown and described in my copending application Serial #77,518, filed December 24th, 1925. In each instance there has been indicated several of the tuned strings selected at random. One such tuned string designated 90 in Fig. 8 and 1T() in Fig. 9 is shown in each of the figures as being substantially in alignment with the pivotal mounting of the reflecting device of Fig. 8 being shown as at 91 in Fig. S. An edgewise pivoted closure 153 (see Fig. 9) is provided with a pivotal mounting as at 171 as described in the copending application referred to. f

Referring to Fig. 10 there is graphically illustrated the variation in area of reflecting surface exposed to the direct action of sound emitted from the string 90, 170, the abscissa representing the angular displacement of the reflector 53, 153 from the fully closed position illustrated in the Figs. 8 and 9. The full line designates the variation in surface area exposed to the direct action of the string 90 in the case of the centrally pivoted reflector 53 and indicates a variation from maximum area at Zero angle displacement from the position shown in Fig. 8 to minimum area at 350 displacement, reverting to maximum G00 displacement, the maxinuun area continuing effective from 60O upwardly. Sii.. ilarly the dottec line shown in Fig. 10 represents the variation in area exposed to the direct action of the string 170 in the case of llt) Y illustrated the variation in area of reflecting surface exposed to the direct action of sound emitted from the string 92, 172, the abscissarepresenting the angular displacement .of the reflector 53 153 from the fully closed position illustrated inthe Figs. 3 and 9. The full line designates the variation insurface area exposed to the direct `action of the string 92 in the case of the centrally pivoted reflector 53 and indicates a variation from maximum area at Zero angle displacement from the position shown in Fig.. 8 to minimum area .at o displacement, increasing until the reflector is at .90o displacement. The minimum reflecting area of the centrally pivoted reflector is less than the minimum reflecting area of the edgewise pivoted reflector. :Thus it Will be seen that the centrally pivoted reflector of Figure 3 provides for an increasedk control of effective sound reflecting surface with respect to the strings 92 and 172.

Referring to Figure 12 there is graphically illustrated the variation in area of reflecting surface exposed to the `direct action of sound emitted from the string 93, 173 of Figures 8 and 9, the abscissa representing the angular displacement of the reflector 53, 153 from the fullj) closed position illustrated in the Figures Y 8 and `9. The full line designates the variation in surface area exposed to the direct action of the spring 93 in the case of the centrally pivoted reflector' 53 and indicates a variation from maximum area at Zero angle .displacement from the position shown in Figure 8 to minimum area at 65 displacement, increasing until the reflector is at 90 displacement. Similarly the dotted line shown in Figure 12 represents the variation in area exposed to the direct action of the string 17 3 in the case of edgewise pivoted reflector 153 of Figure 9 and indicates that the maximum area is exposed to the direct action of sound Waves emitted from the string 17 3, and decreasing to minimum area at o displacement, and again increasing until Athe reflector is at 90O displacement. The minimumreflecting areaV of the centrally pivoted reflector is much less than the minimum reflecting area of .the edgewise pivoted reflector. Thus it Will be seen that the centrally pivoted reflector of Figure 8 provides for an increased control of eective sound reflecting surface with respect to the strings 93 and 173.

The invention upon which .this application is based is broader than the specific enibodiment shown and described for the purpose of illustrating at least one of the Ways in Which it may be employed. The scope of the invention is therefore to be understood as not being limited by the present specific description. 4l intend no limitations other than those imposed by the claims.

lflVhat I claim is:

1. An instrument for producing damped compressional Waves, comprising a vibratory element, a casing therefor, having controllable apertures, and a plurality of sound reflectors rotatably positioned in said apertures for directing Waves producedby said element in a desired direction.

2. In a musical instrument, the combination With a source of sound, of a casing surrounding said source and having an interior reflecting surface to reflect sound, and means for varying the amount of sound reflected back to the source from said surface independentb7 of the total volume of sound produced'.

3. In a musical instrument, the combination with a source of sound, of a casing surrounding said source, said casing having an aperture for emitting sound, a closure for vsaid aperture, the interior surface of said casing and said closure having a layer .of sound reflecting material, and means for variably positioning said closure to reflect desired proportions of sound back into said casing.

4. ln a musical instrument, a plurality of tuned strings, a sounding board adjacent strings, a casing surrounding saidstrings and board, a group of movable reflectors positioned adjacent the strings for reflecting sound Waves in desired directions, a second group of movable reflectors positioned adj acent the'sounding` board for reflecting sound Waves in desired directions, and a single pedal operatively `connected to said reflectors forcontrolling all of said reectors.

5. In a musical instrument, means for producing damped compressional Waves, a casing surrounding said means-said casing having apertures for emitting the Waves, a plurality of closures for said apertures each having a compressional-Wave reflecting surface on its inner surface, and means for controlling said closures to reflect at least a portion of the energy of said Waves back to the Wave producing` means.

6. ln a musical instrument, means for producing damped compressional Waves, a casing surrounding said means, said casing having a compressional Wave reflecting inner surface and provided with apertures,a plurality of closures for said apertures each closure having a compressional Wave reflecting surface on its inner surface, and means for rotating said closures into fully .closed position to form a Wave sustaining chamber Within said casing.

7. In a musical instrument, the combination with a source of sound, of a casing surrounding said source and having an interior reflecting surface to reflectv sound, a sound outlet for said casing, and means for reflecting at least some of the .so-und emitted from the outlet back to thel source of sound for reenergizing said source.

8. The method of producing music Which consists in vibrating a string tuned to a fundamental note, directing some of the energy of the Waves emitted from said string into contact With a second string tuned to an upper harmonic of the funadmental, and varying the intensity of energy so directed.

9. The method of producing music which consists in the step of producing a fundamental tone by percussion, directing compres sional waves corresponding thereto into contact with a string tuned to an upper harmonic of said note, and varying the energy of said directed waves.

10. The method of producing music which consists in vibrating a string tuned to a fundamental note, reflecting Waves emitted from said string into contact with a second string tuned to an upper harmonic of the fundamental, and modifying the intensity of the reflected Waves independently of the action of the string.

11. The method of producing music which consists in the step of producing a fundamental tone by percussion, reflecting compressional Waves corresponding thereto into contact with a string tuned to an upper harmonic of said note, and modifying the direction of reflection of said Waves.

12. In an instrument for producing music, a source of sound, a substantially sound-proof casing surrounding said sound source and having apertures therein, a plurality of centrally pivoted metal lined reflectors positioned in said apertures, and means to vary the area of effective sound reflecting surface.

13. In a musical instrument, the combination with a piano, of a plurality of centrally pivoted metal lined reflectors for variably controlling sound, and means for varying at will the relative amount of sound reflecting surface.

14. In a musical instrument, a plurality of strings for producin sound, a sounding board adjacent said str1ngs, a substantially sound-proof casing surrounding said strings and said board and including a plurality of metal lined sound reflectors, arranged in groups, each of said sound reflectors being pivotally mounted upon substantially its longitudinal axis, said sounding board serving as a partition to divide the casing into two insulated resonating chambers, and means for varying the relative amount of surface of said reflectors effective for reflecting sound.

15. An instrument for producing damped compressional Waves, comprising a plurality of tuned strings, means for striking the strings tuned to a note of the musical scale, a sounding board adjacent said strings, a casing for the instrument having apertures, rcflecting devices positioned in the apertures, and meansfor varying the position of said deviceslwith res ect to the strings to vary the amount of sur ace directly acted upon by sound from the strings.

16. An instrument for producing damped compressional Waves, comprising a plurality of tuned strings, means for striking the strings tuned to a note of the musical scale, a sounding board adjacent said strings, a casing for the instrument having apertures, refleeting devices positioned in the apertures, each of said devices comprising a centrally pivoted flat member having a metal lining on its interior face, and means for varying the position of said devices With respect to the strings to vary the amount of surface directly acted upon by sound from the strings.

17. An instrument for producing damped compressional Waves, comprising a. plurality of tuned strings, means for striking the strings tuned to a note of the musical scale, a Sounding board adjacent said strings, a metal lined casing for the instrument having apertures, reflecting devices positioned in the apertures, each of said devices comprising a centrally pivoted flat member having a metal lining on its interior face, and means for varying the position of said devices with rcspect to the strings to vary the amount of surface directly acted upon by sound from the strings.

18. An instrument for producing damped compressional Waves comprising a vibratory element, a metal lined casing therefonhaving apertures, a plurality of centrally pivoted metal lined sound reflectors positioned in said apertures, and means for rotating said reflectors to vary the amount of sound reflecting surface made effective.

19. In a musical instrument of the percussive type, the combination with tuned vibratory elements, of a substantially sound proof casing enclosing said elements and having opposed apertures for emitting sound, said casing including metal lined Walls intermediate its apertures, and centrally pivoted metal lined reflectors mounted in said apertures and arranged to form in one position closures for said apertures and in other position to modulate the sound by reflection.

20. In a percussion instrument comprising a plurality of strings tuned to different notes, a casing therefor having a sound reflecting lining, movable closures for said casing, and means whereby sound Waves from a Given string may be variably reflected by said closure to a differently tuned string.

21. In a percussion instrument comprising a plurality of strinUs tuned to different notes, a casing therefor llaving a sound reflecting lining, movable closures for said casing, and

means forl reeotng sound VWaves by said variable closure from a given string to a string tuned to n. harmonic thereof.

In an instrument for producing damped colnpressionul Waves having a Vbmtory element and a. Sounding board, a mezzl casing surrounding said sounding board and having `two opposite sides Whose nnguluty with 1"@- vspeci; to the soundlngl board may be valued at JoHN HAVYS HAMMOND, JR. 

